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Decalcify water: How to get the watering water for houseplants and garden plants lime-free

The right location, regular fertilizer applications and watering play a decisive role in plant growth. However, tap water in many regions of Germany contains lime. Some plant species can cope with this, but others cannot thrive on high water hardness, wither, turn yellow and die. In this article, we will tell you why this is so and how you can decalcify the water.

Decalcify water: which plants are sensitive to high water hardness?

Decalcify water methods and home remedies

But why can high water hardness actually have a negative effect on plant growth? Certain minerals in tap water can increase the hardness level. If plants are watered with hard water over a longer period of time, the lime content in the soil increases. Accordingly, the pH of the soil also increases , becoming moderately to strongly alkaline. Especially plants that prefer acidic soil cannot cope with the high lime content. They cannot absorb the nutrients and growth is inhibited and the plant may even die in the worst case.

Plants that prefer lime-free water

Woody plants that prefer acidic soil include rhododendron, azalea, rowan, hydrangea, douglaise, horse chestnut and mock cypress. Grasses and perennials that do best in acid soil include orchid, ferns, iris and daffodil. There are also many crops that prefer acidic soil with pH below 6. Such are, for example, zucchini, radishes, blueberries and potatoes.

Check pH soil Measure values

Whether you should decalcify the irrigation water or not depends, in the first place, on the soil pH, and in the second place – on the types of plants you have in the garden. So, the first step is to determine the soil pH. If you have slightly acidic soil or normal soil, and the plants do best in alkaline to normal soil, then you should decalcify the irrigation water.

A sure sign that the hardness level of the watering water is too high is leaf color. If a white-gray layer forms on the plant leaves after watering, then you should definitely decalcify the watering water.

Decalcifying water for indoor and balcony plants

Decalcify water for balcony plants tips


There are several methods how you can decalcify the water for watering. If you want to decalcify the water for the indoor plants, then you can:

1. check the hardness of the tap water. For this purpose, special test strips are sold in pharmacies. Fill tap water into a clean glass and hold the test strip in the water for about 15 seconds. Depending on how the strip changes color, the degree of hardness can also be determined.

Decalcify water using a jug with a filter

Fill tap water into a pot and boil it. Use a tea filter to remove the lime residue on the surface of the water. Alternatively, you can find in the garden centers special descaler, which is added to the water.

3. Alternatively, you can use a jug with a water filter. To be on the safe side, ask the manufacturer whether the drinking water filter decalcifies tap water.

4.By the way, you can also use the water from the dehumidifier or dryer as watering water for indoor plants.

Decalcify the water for garden plants

Soften water Boil water and let it cool down


The situation is different if you want to decalcify the water for garden plants. In this regard, you have several options:

Boil the tap water

1. fill tap water into a suitable large container and boil it. Then let it cool and use it to water the plants in the garden.

Use rainwater

Watering garden plants with rainwater Tips

2. Water the garden plants with rainwater. Catch it in a rain barrel and use it to water the ornamental and kitchen gardens. Do not water germinating plant and seed with rainwater. It could contain germs and young plants are especially vulnerable.

Decalcify the watering water with coffee grounds, bark or pine needles.

3.Use tap water and then mulch the flower bed with pine needles, coffee grounds or composted bark. They will lower the pH of the soil.

Decalcify the water for watering with vitamin C or vinegar.

Decalcify water with vitamin C home remedy

4. Alternatively, you can add vinegar to tap water or dissolve vitamin C tablets. They can also lower the pH of the soil.

Let the irrigation water stand

Let the water stand and then use it

5. If you have a large garden, then you can simply pour watering water into a barrel and let it stand for about 3 days. The lime will settle to the bottom of the container. You will not get the water completely lime-free with this method, but it is still a good option for long dry periods in the summer.

It is not always necessary to decalcify the irrigation water. It depends mainly on the pH of the soil and the hardness of the tap water. Depending on whether you want to use the irrigation water for the garden or for the indoor or balcony plants, different methods come into question.